How many fish can I fit in my pond?

The burning question: How many fish is the right number for my pond?

With Koi that's an easy question to answer. We recommend no more than one fish per 1 000 litres of pond (not including filter) volume.

And so what size filter do I need?

Koi grow to the size of their bloodline. And if you are buying your Koi from us you will know that Japanese Koi have the biggest growth potential of all Koi. This means that the cute little babies you bought from us a year ago are now not so small and cute but rather sprouting up like the proverbial weeds, whilst eating you out of house and home at the same time. And if you are feeding them one of the Hikari growth diets you will see just why we recommend 1 fish per 1 000 litres.

Even if you are not feeding your Koi with the intent of growing them - the fact that you are feeding them is enough - Japanese Koi from quality bloodlines all have the potential for 70 cm as a minimum, 80 cm as the norm and with any luck over a meter on the odd occasion...

A 70cm Koi is a BIG fish. It will eat a lot and produce a lot of waste. 10 of these in a 10 000 litre pond will; require superb filtration to keep things stable - and hence adding a few extra fish can seriously strain even the best filtration systems. Try a power cut for a few hours to see what we mean...

So, go for fewer fish. We KNOW that this impossible and most hobbyists ponds are hopelessly overstocked. But don't say we didn't warn you!

This is why I like over-specifying on filtration. It adds a margin of safety that can make all the difference between success and utter failure.

You will also see that wherever possible on any pond, I like to specify two independent filtration circuits. This is purely for redundancy in that if something goes wrong with something on the one circuit you will still have the second (or third) one operational and so the consequences of a pump failure, or a broken pipe or a lightning strike on your kit are minimised as far as possible.

The golden rule when it comes to filtration is that when in doubt, go bigger. It can only save you time, money and headaches in the long run.